1. Field of the Invention
Example embodiments relate generally to nuclear reactors, and more particularly to a method and apparatus for a Boiling Water Reactor (BWR) jet pump riser pipe repair with compression that provides hoop and axial strength reinforcement to a riser pipe. The repair may be used to repair a cracked riser pipe, or it may be used as a preventative means of supporting the riser pipe prior to the formation of a crack.
2. Related Art
A reactor pressure vessel (RPV) of a boiling water reactor (BWR) typically has a generally cylindrical shape and is closed at both ends (for example by a bottom head and a removable top head). A top guide typically is spaced above a core plate within the RPV. A core shroud, or shroud, typically surrounds the core and is supported by a shroud support structure. Particularly, the shroud has a generally cylindrical shape and surrounds both the core plate and the top guide. There is a space or annulus between the cylindrical reactor pressure vessel and the cylindrically shaped shroud.
In a BWR, a jet pump assembly is positioned within the shroud annulus to provide reactor core water flow to the reactor. The upper portion of the jet pump assembly, known as the inlet mixer, receives water from a large riser pipe and discharges the reactor water to two diffusers which inject the water into the reactor. The riser pipe is generally supported by a riser brace and the RPV penetration to stabilize the pipe from system vibration and pressure fluctuations during operation of the jet pump assembly. System vibration and pressure fluctuations may ultimately cause minute cracks to form in the riser pipe. The cracks may become exacerbated by continual use of the jet pump assembly. Conventionally, costly repair may be required to replace damaged sections of the riser pipe.